Of the 543 seats up for grabs in the ongoing Lok Sabha elections, at least 25 are special in a certain sense.
These constituencies, spread across 10 states, are bellwether seats which have traditionally been won, most of the times, by the parties which eventually went on to form the government at the Centre.
The oldest among these bellwethers seats is Valsad in Gujarat.
It has been following the trend since its formation in 1957.
Gujarat's 1951 - born Jamnagar, Junagadh and Banaskantha Lok Sabha constituencies are also bellwether seats, with the general elections of 1967 and 1991 being an exception.
In Banaskantha seat, 1996 was also an exception, while in Jamnagar 2009 showed a different trend.
Formed in 1977, the Porbandar Lok Sabha constituency has not followed the trend in 2009 and 2004.
In Delhi, three of the seven Lok Sabha seats are the bellwethers - - East Delhi, New Delhi and Chandni Chowk.
While New Delhi seat has been following the trend since the 1992 by - elections, Chandni Chowk constituency has been a bellwether seat since 1998 and East Delhi since 1996.
Beed in Maharashtra is another such seat which has always elected the party which formed the government at the Centre.
The only exception was 2009 when Gopinath Munde of BJP was elected while the Congress - led UPA was re - elected at the Centre.
The Mumbai North West Lok Sabha constituency has followed the trend since its formation in 1967.